PULSED ELECTROCHEMICAL DETECTION OF ALKANOLAMINES SEPARATED BY MULTIMODAL HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Pulsed electrochemical detection (FED) is applied to alkanolamines sep arated by high-performance liquid chromatography (HPLC). A multimodal HPLC column with both cation-exchange and reversed-phase retention mod es is used with an acidic mobile phase to assure alkanolamines are in their cationic form. Baseline resolution of alkanolamines, including p ositional isomers, is possible. Detector response for a representative alkanolamine, tris(hydroxymethyl)aminomethane (Tris), is shown to be linear over a concentration range of more than three decades. The limi t of detection for Tris is 20 nM (500 fmol in a 25-mu l injection) and the standard deviation of the FED response for 10 mu M Tris is better than 0.4%. HPLC-PED is demonstrated to permit the sensitive and preci se determination of alkanolamines in a biological sample (blood) and a commercial formulation (shaving gel) with minimal sample preparation.